QUESTION: What can you tell me about trigeminal neuralgia? I have had facial pain since 1989, and recently it has gotten to the point where I am unable to eat without excruciating pain. I understand there is an operation that can be done. Can you discuss it? I am fearful of complications. - J.G.

ANSWER: Recapping, neuralgia is nerve pain, and in your case the nerve involved is the trigeminal, which transmits sensation from the face area to the brain. Patients with trigeminal neuralgia, also known as tic douloureux, report brief stabs of wincing pain triggered by the most innocent of forces, such as a breeze or activation of chewing muscles.Surgery is not the exclusive answer. Medicines such as carbamazepine can provide control. Dosage should be adjusted carefully for maximum effect.

If medicine fails, your doctor has a number of surgical procedures available. One involves placing a tiny cushioning sponge around the artery, which at one point encircles the trigeminal nerve. This buffers the artery pulsations that trigger stabs of pain. The surgeon also might opt to deaden the pain-carrying nerve fibers with chemical injection of glycerol, for example. Or a heated probe can deaden the nerve. The last time I discussed the subject, Dr. A.C. of Phoenix wrote me, describing another technique involving compression of the nerve with a small inflatable balloon.

Surgical complications, such as muscle weakness or chronic facial numbness, are rare events. You can discuss such things with your doctor.

QUESTION: In a response to a reader regarding medication for shingles pain, you said Tylenol can help in mild cases, and for more severe pain, you could try amitriptyline or carbamazepine. I have been taking carbamazepine for seizures. Why might the same drug be used for two problems as different as shingles and seizures? - G.E.

ANSWER: This is just one more example of the use of one medicine for different purposes. In fact, if you read the preceding item, you saw carbamazepine popping up as a treatment for trigeminal neuralgia, another nerve-related problem.

I am not certain, but it is a good guess that the drug's multiple uses were discovered while it was being used for seizures in a patient who just happened to have shingles. Examples of such therapeutic serendipity abound in medicine.

For more on shingles, see my shingles report, which is available by writing: Dr. Donohue - No. 28, Box 5539, Riverton, NJ 08077. Enclose a long, self-addressed, stamped (52 cents) envelope and $3.

QUESTION: Have you heard of tobacco smoking being cut off before surgery? It seems rather late to do any good just a few weeks beforehand. - C.S.

ANSWER: During surgery, the patient needs every advantage available. One of them involves the availability of oxygen to the tissues. Smoking decreases such oxygen delivery and prolongs healing.

Chronic smokers encounter healing delay from even everyday cuts and scratches.

Your surgeon's restriction is the rule rather than the exception today. You should continue to avoid tobacco after your surgery as well, for all the other good reasons.